I've seen that levequest.

Lord Haurchefant is brawny (as far as I know). He's certainly not frail at all. IDK that's a weird one. There are multiple families under each House when you start including servants, knights, craftsmen etc. The phrase "THE" lord of House Fortemps makes this one confusing, though. Neither the Count nor any of his sons mention a fourth child, but maybe that's a plot point the MSQ hasn't gotten to yet who knows.